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UNITED STATES PATENT rFrcE.

HARRY L. HAAS, OF NEXV YORK, N. Y., ASSIGNOR OF ONE-FOURTH OF HIS RIGHTTO ALEXANDER LEVETT, OF SAME PLACE.

SOLUTION FOR NICKEL-PLATING.

SPECIFICATION forming part of Letters Patent No. 230,872, dated August10, 1880. Application filed February 18, 1880.

To all whom it may concern:

Be itknown that I, H. L. HAAS, of the city, county, and State of NewYork, chemist, have invented certain new and useful Improvements in theArt of Nickel-Plating, consisting of a new process of securing theelectro-deposition of nickel.

In order to enable others to practice my invention, I do hereby declarethat the following is a full and exact description thereof.

My invention relates to an improvement in the art of nickelplating; andit consists in the employment of a solution containing formate ofnickel, with excess of acid, as hereinafter more fully set forth.

I use as an anode an ordinary cast nickel plate prepared in any of theusual methods. I take the green oxide of nickel, well known as anarticle of commerce, or I form oxide of nickel by dissolving commercialnickel (the purer the better) in nitric acid, thereby forming a nitrateof nickel. This should be evaporatedto dryness, and when heated leavesthe green oxide of nickel. The oxide of nickel is 2 then dissolved informic acid. The resulting solution is the formate of nickel. Thissolution should be diluted. I have obtained excellent results when suchsolution has a specific gravity of 1.050, water being 1.000; but use- 0ful results may be accomplished within a wide range of strength of thesolution, and. good results may be obtained when the solution is muchweaker than is above stated. The weaker the solution, however, thelonger time is required to obtain the deposit under the same conditions.

Formate of nickel is capable of crystallization, and therefore can bemanufactured and sold in a cheap and convenient form ready for use, andcould be used by any nickel-plater simply by dissolving it in water.

WVhen the solution is prepared the anode and cathode are immersed in it,and the electric battery is applied. With the solution of 5 the specificgravity of 1.050 I have used a Daniell battery of three cells or aBunsen battery of one cell. m

The action of the battefiupon the formic acid in the solution of theformate of nickel is such that carbonic-acid gas and oxygen go to theanode and metallic nickel and hydrogen go to the cathode, and the nickelis deposited.

Instead of using the oxide of nickel in forming the solution, thehydrated oxide of nickel may be employed, and such hydrate may beprecipitated from any solution of nickel by an alkali, such as potash.The hydrate so formed may be washed, and when dried is dissolved in theformic acid.

It is not necessary that the solution which I employ should be free frompotash, soda, lime, or alumina, or even from traces of nitric acid, forarticles which have been cleaned by such alkalies or acid, and which areleft by careless workmen with a little of such substances adhering, willnot affect my solution.

The result of using the solution aforesaid is the electro-deposition ofa firm, coherent, and continuous deposit of clean and white nickel, 7cand the use of such solution possesses the following advantages over anyprevious process with which I am acquainted:

First, it is an acid solution, and the battery-currentdoes not affect itwithin any reasonable limits of intensity.

Second, it contains no ammonia. Hence there is no liability todecomposition and the liberation of free ammonia by the use of a highbattery power, which impairs the value of other solutions.

Third, the process is a continuous one, and the solution needs noreplenishing with salts of nickel, the nickel being supplied from theanode.

Fourth, no precautions need be taken to see that the solution is freefrom the presence of potash, soda, alumina, lime, or nitric or otheracid.

Fifth, the deposit may be of any thickness, 0 and will always be firm,flexible, and white.

It will be perceived that the-basis of my invention is the use of adiluted solution of formate of nickel containing an excess of acid, andthat this solution requires less care and is 5 cheaper in managementthan anysolution with which I am acquainted.

When the formate of nickel is used as above specifically described theonly precaution which it is necessary to observe is that the ar- :00

What I claim, and desire to secure by Letters Patent, is- 1 In the artof nickel-plating, a solution eon-. taining formate of nickel withexcess of acid, and diluted to the required strength, substangially asdescribed, and for the purpose set orth.

HARRY L. HAAS.

Witnesses:

SAML. R. BETTS, J. L. HAAS.

